Concrete Calculator – Cubic Yards for Any Project
Calculate cubic yards of concrete needed for slabs, footings, columns, and steps. Includes bag count for small projects.
🏗️ Construction📐 Volume = Length × Width × Depth (in feet) / 27
Length (feet)
Width (feet)
Depth (inches)
Please enter valid values.
Formula & Reference
| Variable | Formula | Units |
|---|---|---|
| Concrete Calculator – Cubic Yards for Any Project | Volume = Length × Width × Depth (in feet) / 27 | cubic yards |
Step-by-Step Examples
Example 1
Patio 20×12 ft, 4 in
20×12 ft, 4 inch depth.
- Volume: 2.96 cu yd | With waste: 3.26
- ~100 60-lb bags
✓ 2.96 cu yd
Example 2
Sidewalk 50×3, 4 in
50×3 ft × 4 in.
- Volume: 1.85 cu yd | 83 60-lb bags
✓ 1.85 cu yd
Example 3
Driveway 20×40, 4 in
20×40 ft × 4 in.
- 9.88 cu yd — order ready-mix!
✓ 9.88 cu yd
Real-World Applications
Contractors
Calculate concrete for any slab or footing.
DIYers
Order the right amount of concrete bags.
Estimators
Quick concrete takeoff for bids.
Builders
Verify quantities before pouring.
Common Mistakes to Avoid
⚠️
Not adding 10% waste
Always add 10% buffer. Running short of concrete mid-pour is a major problem.
⚠️
Bagged vs ready-mix
Over 1 cubic yard: order ready-mix. It's cheaper and better. 1 yard = 45 60-lb bags.
Frequently Asked Questions
How much does concrete cost? ▾
Ready-mix: $120-200/cu yd. 80-lb bags: ~$6 each. 1 cu yd = 34 80-lb bags.
Minimum ready-mix order? ▾
Most suppliers: 1-yard minimum. Short-load fees apply. Use bags for under 1 cubic yard.
How thick should a slab be? ▾
Walkways: 4 in. Driveways: 4-6 in. Garage floors: 4-6 in.